1. Field of Invention
The invention relates to information processing, and more particularly to advanced storage and retrieval of audiovisual data objects.
2. Description of Related Art
In the wake of rapidly increasing demand for network, multimedia, database and other digital capacity, many multimedia coding and storage schemes have evolved. Graphics files have long been encoded and stored in commonly available file formats such as TIF, GIF, JPG and others, as has motion video in Cinepak, Indeo, MPEG-1 and MPEG-2, and other file formats. Audio files have been encoded and stored in RealAudio, WAV, MIDI and other file formats. These standard technologies have advantages for certain applications, but with the advent of large networks including the Internet the requirements for efficient coding, storage and transmission of audiovisual (AV) information have only increased.
Motion video in particular often taxes available Internet and other system bandwidth when running under conventional coding techniques, yielding choppy video output having frame drops and other artifacts. This is in part because those techniques rely upon the frame-by-frame encoding of entire monolithic scenes, which results in many megabits-per-second data streams representing those frames. This makes it harder to reach the goal of delivering video or audio content in real-time or streaming form, and to allow editing of the resulting audiovisual scenes.
In contrast with data streams communicated across a network, content made available in random access mass storage facilities (such as AV files stored on local hard drives) provide additional functionality and sometimes increased speed, but still face increasing needs for capacity. In particular, taking advantage of the random access characteristics of the physical storage medium, it is possible to allow direct access to, and editing of, arbitrary points within a graphical scene description or other audiovisual object information. Besides random access for direct playback purposes, such functionality is useful in editing operations in which one wishes to extract, modify, reinsert or otherwise process a particular elementary stream from a file.
However, there has not yet emerged a stable and widely available coding and storage scheme which permits flexible, efficient and consistent processing of both streaming and mass-stored AV information in a uniform format, at any level of scene granularity desired.